Hydropower Generator

[Paul] wanted to have access to renewable energy at his cabin. It’s a relaxing place, nestled in a tall forest that shelters him from the sun and wind. This also means that solar and wind energy aren’t an option. But there is a stream running through the property so he decided to build his own version of a small water-powered generator.

He tapped into a reservoir about 200 feet upstream, split the flow into four smaller hoses, and channeled that into a five-gallon bucket. Inside the bucket you’ll find a Pelton wheel he built which turns a low-RPM generator. He manages to generate 56 VDC at 10 A with this setup, more than enough to charge a bank of batteries.

He does a great job of explaining his setup in the video after the break. If you’re looking for other ideas of how to cut down on your environmental impact check out this compost-powered water heater.


36 thoughts on “Hydropower Generator

  1. This is not a niewe idee
    i see it before
    on discovery chanel whas a program
    about green seltion on problems
    it whas whit tha colenel dick from screpheap chalens en u athur guy
    i dont no that program name

  2. might wanna consider putting a screen over the feed end up river, and drill a hole or two in the pipe near the top and put screens over those too. that way you can keep the flowrate unchanged, but keep foreign objects out.

  3. I can’t wait to see this thing refined. This could potentially be a very very good way to power your junk out in the woods. Surely this isn’t viable all over the country/world due to the height difference required, but nonetheless it can be useful.

  4. I have always wanted to use a stream or river for power generation; you could couple the torque for use with machines (such as a heat pump for your fridge) to increase efficiency over electric generation -> motor transition, which has two lossy transduction processes. Turn a mill, run fans for air circulation, washing machine, what have you.

  5. Haha! This is so cool!!!

    My family has a place on lake michigan, where there is almost constant waves (sometimes very large ones). I have been considering trying to make some device that would create power from the back-and-forth motion of that water….

  6. I’m getting

    (56 * 10 * 24) /1000 = 13.44 KWH per day

    (V*A*hours)/convert to KWH

    So he’s making the equivalent of maybe a $65/month power bill. That’s plenty for me at home unless I need to heat or cool with it.

    He should be able to plug in, as is, any motorized tool that takes brushes (look for two prong plugs, “double insulated”, or universal motors) and run them pretty well at 56 volts. Off the top of my head, that’s my power drill, my circular saw, and my blender (for adult beverages at the end of the day)

    Pretty cool.

  7. I’d be careful about how long he lets this thing run uninterrupted. It looks like the parts he used in the actual turbine disk are not going to take kindly to the type of fatigue they’ll be susceptible to.

  8. @ ferdi
    Yeah, I know what you mean. That show had some good ideas, some less practical ones, but it was a lot of fun.

    But please use some resources on the ‘net to improve your English spelling. (you seem Dutch, from your spelling, net als ik)

  9. I don’t think he can really draw 560 W out of this thing. According to the chart he references, the 56V is at no load (zero current), and the 10A measurement is when the output is shorted. So the Thevenin equivalent circuit would look like a 56V supply and a 5.6 ohm resistor. Maximum power transfer will happen when the load resistance is equal to the Thevenin resistance, so maximum power transfer will have only 5A flowing and the voltage seen across the load will be about 28V, so the power transferred would only be 140 W.

    I could be wrong – I haven’t actually worked with this alternator, or maybe I am mis-applying the theory here. But it looks to me like he would only be able to pull 140W from this thing.

  10. This setup won’t produce 560 watts. 56 volts is the open circuit voltage. When loaded, the output will be less. From the DC-540 tech data:

    “Voltage readings were recorded with the circuit open (No Load) while Amperage was recorded with the output shorted (Max Load)”

    The actual voltage and current output will be somewhere between those two values depending on the load.

  11. To regulate the flow automatically in summer he could use a small motor attached to the valve already in place in some way. Then you would have a good 2 inch automatic valve

  12. Everybody please, c’mon when there is any load of some sort the mechanical stress on the alternator will stall the whole thing in no time. With this setup I estimate a max power of 20 Watt.

    Of course the 20 Watt is a rough estimation. But if u don’t believe the other bit, try to turn a electrical (permanent magnet motor) with an without a load en notice the difference in torch needed to turn de rotor.

  13. I’ve been thinking of doing something similar for my apartment. We pay for electricity, but not for water. :)

    Of course, that would be a terrible idea, but it’s an interesting thought…

  14. Hey Danny,

    As mentioned in the article the output is sufficient to charge a bank of batteries, so the use is much like a solar panel. Any large instantaneous current demand would be supplied by the batteries and not choke out the generator.

  15. Right, we all appreciate that its a large generator, but it is being tested under no load. When you try to take electrical power out of it to do work, there will be a force that opposes the motion of the axle, proportional to the amount of power you are taking from it.

    If you have any little motors lying around, try spinning it with and without the contacts shorted. Its becomes very hard to spin to spin when they are shorted.

    20W sounds low, but his point is that the generator will simply stop spinning if you try to take too much power from it. It will definately not be spinning anywhere near the speed in the video.

  16. Let’s approach it from the physical side: you cannot get more energie out of a system than you put into it. 1.7 liters of water per second via a 2″ pipe means a mass of 1.7 kg moving at a speed of 0.8 m/s (sorry, I have to switch to metric here ;). This gives a kinetic energie of 0.57 Joule/sec which is .. 0.57 Watts. I know, this sounds pretty low but I dont’s see an error in my calculation at the first glance.

  17. Ooops, big mistake in my calculation: to estimate the velocity of the water exiting the nozzles, one has to calc with the diameter of the nozzles (4x 1/2″) and not with the diameter of the feeding line, like I did. This results in a much higher egress velocity (13 m/s), leading to a total maximum power of over 140 Watts. Because the turbine design isn’t that close to an optimal pelton turbine, I would probably expect to see about 100 Watts of electrical power at the output of the generator. I really would like to see some real world measurments of Pauls setup for comparsion :-)

  18. I thought the only load he was looking at was charging batteries. Maybe I haven’t thought this through sufficiently, but it seems to me that if you put a load on a bank of batteries, they shouldn’t drop substantially enough to shut down the alternator.

  19. Nice idea

    To regulate the flow I would use a centrifugal governor . It is purely mechanical and works well on things that have uneven pressure. They were designed for use on steam engines because steam wasn’t usable at the time because it would deliver pressure in spurts and high and low depending on temperature could drive a machine too fast or slow. You would attach a shaft that has a hole through the shaft on one end to your water generator and put a short length of wire through that hole. Glue or epoxy the wire so it doesn’t slide out with equal lengths of wire on each end. On each end of the wire put some lead weight. The wire needs to be flexible enough so that with the weight applied it falls down beside the shaft. As the shaft picks up speed the weights will fly out, the faster it spins the more they will raise up and slow down the shaft regulating the speed. You will have to experiment with the amount needed to get the desired effect.

    For bringing the water to the generator I would use vinyl tubing not PVC. PVC has a large loss to friction that really adds up over distance as well as the pressure loss from every elbow added. Vinyl can keep almost the same pressure all the way to the end even with lots of turns.

    The generator I would improve by increasing the surface area that the water contacts inside . Cut some 2″ pvc in half lengthwise about 12″ long . Arrange them so they are vertical forming a circular shape with a center axis. That should up the contact area and lower the water requirement.

    Another thing you can try is a water wheel . It depends on the height that you can raise the water above the wheel and lets gravity help to increase the water force. A 1″ pipe at 20psi can drive a pretty large wheel if the water falls from about 5 feet above it.

    A good solar panel based charger would work well here .

  20. You probably only need to charge a notebook and cellphone, and power fluorescent or LED lighting for a couple hours per day.
    The water stream runs 24 hours per day, so with a big bank of batteries you might even have power to spare.

  21. Can he take the water coming out and run it back in? Mainly with a one way valve before the 4 hole inlet. If so it would seem like you could have an over unity machine. Or how about the water gets collected and heated by an electronic coil cased off the heat output of the motor to create a turbine steam engine? I’d be very curious for a reply.

  22. Did I miss where he mentions Amps? If he is purely using this to charge batteries then it would work using a charge regulator which would vary the load applied to the generator to obtain max current from it without stalling it. This would then charge his battery bank.

  23. When charging batteries, you can’t really stall the generator, because when it slows down, the voltage drops (I assume, if it’s not regulated), and so the current drops as well, which means the required torque drops. You just needs some simple electronics to keep the batteries from overcharging, and from driving the generator when there is little or no water to drive it. Of course this only works with permanent magnet generators, not with alternators.

    If you would attach a switchmode power supply, you could stall it; these power supplies effectively have a negative input impedance, when the voltage drops, the current has to rise, to keep the power constant for the output (neglecting losses, of course).

    @Itwork4me: you might consider taking some physics classes when you grow up.

  24. Sp`ange,

    You’re never going to generate more power than it takes to pump the water back into the basin.

    I have 16 acres in Tennessee that has a small, year-round stream on it, and I plan on doing something like this.

    Any thoughts on using a induction propellor from a jetski to turn a perminent magnet generator using a 4 inch PVC Pipe, much like a Kaplan turbine. Given that I have enough head, of course.

    Any thoughts would be more than welcome.

    As to usage; this will be for a completely off-grid reirement home with a bank of deep-cycle PV batteries, coupled with solar and wind power generation.

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